1. Field of the Invention
The invention relates to a misfire determination device for an internal combustion engine, and more particularly, to a misfire determination device for the internal combustion engine in a hybrid vehicle that is equipped with an internal combustion engine including a plurality of cylinders that can output a motive power for running and an electric motor that is mechanically connected to an output shaft of this internal combustion engine.
2. Description of Related Art
Conventionally, as this kind of misfire determination device for an internal combustion engine, that which detects a driving condition of a hybrid vehicle based on an operation state of an electric motor of the vehicle, and which determines whether or not the vehicle is driven on a condition that may lead to fulfillment of a condition of erroneous detection of a misfire in an internal combustion engine has been proposed (e.g., see Japanese Patent Application Publication No. 2001-317402 (JP 2001-317402 A)). With this device, when it is determined that the vehicle is driven on the condition that may lead to fulfillment of the condition of erroneous detection of a misfire in the internal combustion engine, a misfire detection process is suppressed or suspended. Thus, erroneous detection of a misfire in the internal combustion engine is more reliably avoided.